Comparison between MR imaging and pathological findings of the liver and VX2 carcinoma in rabbits after ethanol injection

Ethanol injection was performed in the liver and VX2 carcinoma in rabbits and we evaluated changes with time by MR imaging, including dynamic study, and pathological findings. In the liver, the necrotic region was demonstrated as an area of low signal intensity on T 1-weighted images and one of high intensity on T 2-weighted images. Dynamic study after one and two weeks showed no enhancement in the necrotic region. But after a month, the pathologic analysis revealed growth of abundant fibrous stroma replacing the necrotic region, and progressive, concentric enhancement was seen in the necrotic region on dynamic study. On T 1-weighted images obtained after the administration of contrast medium, delayed enhancement suggesting that the necrosis contained tissue with abundant interstitial space was seen. In VX2 carcinoma, the necrosis in the tumor was demonstrated as an iso or high signal intensity area on T 1-weighted images and an area of low intensity on T 2-weighted images, and did not show enhancement as in the dynamic study of the liver. From the pathological analysis, the presence or absence of space containing water among the necrotic cells was suggested to be responsible for these different findings on T 1- and T 2-weighted images between the liver and VX2 carcinoma after ethanol injection. (author)